The invention relates to a machine for turning over of mesh reinforcement grids, emerging from mesh reinforcement welding machines, through 180.degree..
In the majority of the mesh reinforcement welding machines used nowadays the grids are made in horizontal positions with the longitudinal rods at the bottom and transverse rods at the top. On stacking the grids directly as they emerge from the mesh reinforcement welding machine on top of each other, the transverse rods of one grid lie against the longitudinal rods of the next grid at right angles.
However, if every other grid emerging from the mesh reinforcement welding machine is turned over through 180.degree. about the longitudinal axes of the grids, then whilst the longitudinal rods in the first grid, which is not turned over, are situated below and the transverse rods at the top, on the second, turned-over grid, the transverse rods are at the bottom and the longitudinal rods at the top. The third grid, which once again is not turned over, has once again the longitudinal rods at the bottom and the tranverse rods at the top. Thus, it can be seen in this manner of stacking, the longitudinal rod groups of two grids which are situated one on top of the other and subsequently the transverse rod groups of two grids lying one on top of the other, are located in the same plane, whence the height of the mesh reinforcement grid stack can be reduced to half the value which would be obtained on stacking all grids in the same relative position.
In a known machine for turning over of the grids (DE-AS No. 2 060 219) a supplied grid picked up above the stacking station, lifted and turned over its longitudinal axis, it is lowered again and after a second grid which is not to be turned over has been supplied is, together with the latter, released on to the stack. This known arrangement is characterised by a guide frame with holding elements which travel apart and are used for picking up and releasing of the grids, and in which the frame is moved via swivelling arms between a lower picking up and an upper reversing position in which the frame can be turned over about its longitudinal axis.
Since in the known arrangement it is necessary to push a second grid onto the frame after turning over of the first grid and subsequently lowering to the initial position, before both grids can be released together for stacking, the stacking process is delayed.
In the known arrangement the frame is first moved away parallel to itself by a swivelling movement of the swivelling arms out of the feed path of the mesh reinforcement grids, and is then turned over in the same sense as the previous movement of the swivelling arms (now at standstill) and subsequently is returned by return swivelling of the swivelling arms parallel to itself into the feed path of the mesh reinforcement grids. The consequence of this is that the overall time used for the upwards swivelling, turning over, and return swivelling of the frame is relatively long, quite apart from the consideration that the turned-over frame must yet be loaded with the second grid, before the two grids, finally picked up by it, can be deposited on the stack. Especially in the case of modern, high rate welding machines, in which the longitudinal as well as the transverse rods are drawn from storage coils and processed in a continuous operation into interconnected continuous mesh reinforcement of great length, from which grids of required length are separated after the welding operation, the known turning over arrangements between the welding machine and the turning over arrangement require long outlet surfaces, which are used as storage for the mesh reinforcement which emerges continuously from the welding machine up to its separation into grids and for their picking up in the turning over machine. The space requirement of machines provided with these turning over arrangements is hence relatively great in the mesh reinforcement supply direction.
In addition the frame must be longer by an appreciable amount that the width of the widest mesh reinforcement grid to be turned over in order to ensure the separation of the holding elements on the frame for releasing of the grid held by them. Hence, the space requirement across the mesh reinforcement feed direction is also relatively great.
In addition to the great space requirement both these factors also cause increased material demand for the construction of the turning over machine and of the outlet surface to be provided in front of it. As a further consequence also the weight of the moving parts becomes greater, which once again results in higher demand for driving power.